CN105538033A - Machining method of fiber reinforced type high-temperature composite used for aircraft engines - Google Patents

Abstract

The invention provides a processing method for fiber-reinforced high-temperature composite materials used in aero-engines. Aiming at defects such as tearing, splitting, delamination, fluffing, and dimensional instability that often occur during processing, it is proposed to use a cooling liquid during processing. It is a mixture of water, glycerin, and animal oil, with a volume ratio of 8-10:4-5:4-5. It has good lubricity and can absorb dust generated during processing, and is also environmentally friendly. A tool is also used, the diameter of the tool handle is thicker than ordinary, and the tool is cut along a plane at 45° to the fiber direction of the fiber-reinforced high-temperature composite material during cutting, which can effectively improve the shock resistance of the turning tool. In addition, when drilling a workpiece with a large curvature on the surface, make an accessory that fits the curved surface completely, and the drill tool passes through the accessory hole, which can prevent the workpiece from being damaged by vibration and a small amount of displacement during processing. Size deviation.

Description

Processing method of fiber-reinforced high-temperature composite materials for aero-engines

technical field

The invention relates to the processing technology of composite materials, in particular to a processing method of fiber-reinforced high-temperature composite materials for aero-engines, including two processing technologies of curved surface shape cutting and drilling.

Background technique

Fiber-reinforced high-temperature composite materials for aero-engines are composite materials with carbon and ceramics as the matrix and certain carbon fibers and ceramic fibers as reinforcements. They have high specific strength, high specific modulus, high temperature resistance, corrosion resistance, fatigue resistance, and With a series of excellent properties such as creep, electrical conductivity, heat transfer and small expansion coefficient, it can be used not only as a structural material to carry heavy loads, but also as a functional material. Fiber-reinforced high-temperature composite materials for aero-engines are also widely used in the aerospace field, but they are typical difficult-to-machine materials due to their high hardness, high strength, anisotropy, poor thermal conductivity, and inability to liquid cooling. The matrix and reinforcing fibers are the main elements in the cutting process. At the same time, the cutting is also affected by factors such as fiber orientation distribution. The anisotropy of the material leads to defects such as tearing, splitting, delamination, and fluffing in the processing of composite products. These The appearance of defects leads to the reduction of mechanical properties and surface roughness of composite materials, and many large components of this material require high-precision machining, while ordinary turning has disadvantages such as low machining accuracy, low efficiency, serious tool wear, and high cost. Difficult to meet processing needs.

Therefore, how to design a processing method for fiber-reinforced high-temperature composite materials for aero-engines to improve dimensional accuracy and reduce material performance damage is a problem that needs to be solved.

Contents of the invention

In view of the above demands, the present invention provides a processing method of fiber-reinforced high-temperature composite materials for aero-engines, in particular, due to the use of special coolant and cutting tools in the processing, the wear of the cutting tools on the workpiece during the processing is reduced, and the Improve the surface finish and dimensional accuracy of the workpiece, and reduce the performance loss during processing.

The purpose of the present invention is mainly achieved through the following technical solutions: a processing method for fiber-reinforced high-temperature composite materials for aero-engines, which is characterized in that a cooling liquid is used in processing, and the cooling liquid is water, glycerin, The mixed liquid of animal oil, the volume ratio is 8-10:4-5:4-5.

Further, the animal oil is lard.

Further, the volume ratio of the water, glycerin and animal oil is 2:1:1.

Further, the preparation method of the cooling liquid is: firstly mix water and glycerin with a volume ratio of 3.2-5:1 at room temperature to form a mixed liquid one, and mix glycerin and animal oil with a volume ratio of 0.8-1.25:2 Mix to form mixed liquid 2; and then use the same volume of glycerin as a benchmark to uniformly mix the mixed liquid 1 and the mixed liquid 2 to obtain the cooling liquid.

Further, the processing method also includes using a tool, the tool includes a handle and a blade body, the handle is made of hard alloy steel, and the diameter of the handle is 1.5-5 times that of a common handle; The knife body is submerged into the knife handle by melting the knife handle, and the shape of the part of the knife body immersed in the knife handle is an inverted trapezoid.

Still further, when the tool is cutting, it performs cutting along a plane that is 45° to the fiber direction of the fiber-reinforced high-temperature composite material.

Still further, the processing parameters of the tool are: feed rate f=(0.01-0.04) mm/r; cutting depth ap=(0.05-0.2) mm; amplitude A=15-30 μm. Preferably, feed rate f=0.02mm/r; cutting depth ap=0.1mm; amplitude A=25μm.

Further, the method also includes a method of drilling the curved surface of the workpiece of the fiber-reinforced high-temperature composite material:

Firstly, an auxiliary fitting that fits perfectly with the curvature surface of the workpiece is made, and the auxiliary fitting is drilled in advance as a tool entry hole;

Then attach and fix the auxiliary fitting to the workpiece, and correspond the drilling positions on the auxiliary fitting to the drilling positions on the workpiece;

Finally, the tool is inserted into the drilling hole of the auxiliary accessory to drill holes on the workpiece.

Still further, the diameter of the hole on the auxiliary fitting is equal to or slightly larger than the hole to be drilled on the workpiece.

The beneficial effects obtained by the present invention are as follows: 1. Due to the use of a special cooling liquid, the present invention has good lubricity and can effectively absorb dust generated during processing, and is also environmentally friendly. 2. A new structural tool is provided, which has high strength and is suitable for processing hard parts such as fiber-reinforced high-temperature composite materials. 3. Cutting along the 45-degree direction of the fiber can be used in the processing method, which can effectively cut in without destroying the structure of the fiber, and effectively reduce the tearing, splitting, delamination, and fluffing that often occur in the processing of fiber-reinforced high-temperature composite materials. And defects such as dimensional instability. 4. The present invention also provides a method for precisely machining a hole in a piece with a relatively large curvature on the surface.

Therefore, the present invention is suitable for processing structures under the fiber-reinforced high-temperature composite materials, such as aircraft engine structural parts (such as inner cones, etc.), moving discs and static discs of aircraft brake discs, high-speed rail brake discs, and advanced racing car brake discs. And special crucibles, etc.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be considered as limitations of the invention, and like reference numerals refer to like parts throughout the drawings.

Fig. 1 is the structural diagram of the cutter that the present invention uses;

Fig. 2 is the embodiment figure of processing drilling on the cylindrical workpiece surface;

Fig. 3 is a diagram of auxiliary accessories for drilling holes on the cylinder;

Fig. 4 is an assembly drawing of the cylindrical part and the auxiliary parts.

detailed description

In order to enable those skilled in the art to better understand the technical solutions of the present invention, and to make the above-mentioned purpose, features and advantages of the present invention more obvious and understandable, the present invention will be described in further detail below in conjunction with examples, but the present invention does not Restricted thereto, that is, modifications made to the technical idea of the present invention, and other configurations or configurations are of course included in the present invention.

The invention provides a processing method of fiber-reinforced high-temperature composite materials for aero-engines. On the one hand, it specifically refers to the use of a special self-made coolant for cooling and lubrication during processing, which reduces the wear of the tool on the workpiece during processing. .

Due to the fiber-reinforced high-temperature composite material itself has the characteristics of low density, electrical conductivity, high strength and high modulus, at the same time, there will be very small fine dust during the processing of carbon fiber reinforcement and carbon matrix, and it is difficult to dissolve with ordinary coolant , so it is easy to adhere to the sample and float in the air during the processing vibration process, which affects the accuracy of the processing process and damages the electronic components in the equipment. Using a new type of coolant, because of its good lubricity, the vibration reduction effect is better, and the damage to the material and the knife edge during the processing is better. At the same time, a large amount of dust generated during the processing of composite materials, the new type of coolant also has better performance. Absorbent properties.

Therefore, the present invention adopts a new type of cooling liquid, the formula is a mixture of water, glycerin and animal oil, the volume ratio is 8-10:4-5:4-5, animal oil is preferably lard, and the volume ratio is preferably 2:1:1 .

Glycerin and animal oil have excellent lubricity and certain adsorption capacity, and water has a large specific heat capacity, which is a necessary component of coolant. Among them, animal oil can effectively reduce the wear of tools on workpieces during processing. Glycerin can be miscible with water and can It is miscible with animal oil and is an important intermediate. At the same time, glycerin can also improve the surface activity of the mixed liquid, improve the liquid's ability to absorb dust generated during processing, reduce environmental pollution, and be more environmentally friendly. In the case of ensuring that the three can be effectively miscible, the ratio is more appropriate.

The preparation process of the cooling liquid is: at room temperature, water and glycerin with a volume ratio of 3.2-5:1, and glycerin and animal oil with a volume ratio of 0.8-1.25:2 are mixed uniformly, respectively called mixed liquid and mixed liquid two; then based on the same volume of glycerin, the mixed liquid one and mixed liquid two are mixed evenly to obtain the cooling liquid.

After the coolant is prepared, store it in a cool place at room temperature.

The invention provides a processing method for fiber-reinforced high-temperature composite materials for aero-engines, and specifically refers to a method for cutting materials. The present invention is aimed at the three-dimensional high-temperature composite material with carbon and ceramics as the matrix, adding certain carbon fibers and ceramic fibers as reinforcements. When cutting, it adopts a plane at 45° to the fiber direction for processing, so that the best processing effect can be obtained. .

Furthermore, a self-made cutter is used for cutting. As shown in Figure 1, the characteristics of this tool are: First, this tool uses hard alloy steel as the handle material, the handle 1 is thickened, and the diameter is about 1.5-5 times that of the ordinary handle The tool handle 1 can effectively improve the vibration resistance of the tool, thereby reducing damage to the workpiece. Secondly, the knife body 2 is submerged into the knife handle 1 by melting the handle. The specific process is to first melt the material of the knife handle 1 with an appropriate mold, and then press the knife body 2 into the knife handle 1, and then cool and form it. Again, the shape of the part where the knife body 2 is submerged in the knife handle 1 is an inverted trapezoid. As shown in FIG. 1 , the inverted trapezoid embedded can make the knife handle 1 and the knife body 2 more firmly combined. Again, the blade 2 can be made of cemented carbide or synthetic diamond material, and synthetic diamond will enhance the cutting strength even more.

Further speaking, the specific processing parameters of the cutting tool are set as follows: feed rate f=(0.01-0.04)mm/r, preferably 0.02mm/r; cutting depth ap=(0.05-0.2)mm, preferably 0.1 mm; amplitude A=15-30 μm, preferably 25 μm. These parameters are data summed up after specific processing. If the speed is too low, the efficiency will be low; The processed surface will be uneven and the damage to the blade will increase.

The processing method of fiber-reinforced high-temperature composite materials for aero-engines provided by the invention also specifically refers to a method for drilling such materials. When the present invention drills a workpiece with a larger curvature on the surface, such as a cylinder as shown in Figure 2, when drilling a hole on a cylindrical workpiece 3, the processing method adopted is: firstly make Attached auxiliary fitting 4, as shown in Figure 3, and the auxiliary fitting 4 is drilled in advance as a tool entry hole; then the auxiliary fitting 4 is fixed to the workpiece 3, and the position of the drilled hole on the auxiliary It corresponds to the drilling position on the workpiece 3; finally, the tool extends from the drilling hole of the auxiliary accessory 4 to drill on the workpiece 3. Such a processing method can prevent the workpiece 3 from splitting during processing and dimensional deviation caused by vibration and small displacement. Furthermore, the auxiliary accessory 4 is a metal piece, which can prevent the accessory from being split or deformed due to excessive drilling force during drilling.

Further speaking, the hole on the auxiliary fitting 4 is equal to or slightly larger than the hole to be drilled on the workpiece 3, so that the tool can be inserted.

As for the fixing form of the auxiliary fitting 4 and the workpiece 3, any feasible method can be adopted, such as fixing with a clamp, or connecting with a pin, or using rope binding and other measures.

In order to verify the technology of the present invention in the above aspects, the present invention provides the following examples.

Embodiment 1: Processing of aircraft brake disc

Before the processing of aircraft brake discs, 1. Make a special tool in advance: choose hard alloy steel as the tool handle material, the tool handle is thickened, and the diameter is 9mm, which is about 1.5 times thicker than the ordinary tool handle of the same specification; melting The knife handle, the knife body is immersed in the knife handle, the shape of the part where the knife body is immersed in the knife handle is an inverted trapezoid, and the knife body is made of artificial diamond material. 2. Mix water, glycerin and lard according to the volume ratio of 2:1:1 to make cooling liquid for later use.

In the process of processing, fix the tool and the workpiece, set the processing parameters for processing, and set the two steps of rough and finish processing, all of which use special tools to process along the plane at 45° to the fiber direction. The specific parameters are feed rate f=0.02mm/r, cutting depth ap=0.1mm, amplitude A=25μm. The measured machining accuracy of the workpiece is: the error is less than 30 μm.

Embodiment two: the processing of sealing sheet

Same as Example 1, the special cutting tool and coolant are prepared in advance, and the workpiece is fixed with a fixture during processing; during processing, the hard alloy body is used for rough processing, and the processing is carried out along the direction of 45° with the fiber direction, and the processing The specific parameters are feed rate f = 0.02mm/r, cutting depth ap = 0.1mm, amplitude A = 25μm; after rough machining, the artificial diamond polycrystalline body is used for finishing machining, and the same method is used at 45° to the fiber direction. The surface is processed, and the processing parameters are still the feed rate f=0.02mm/r, the cutting depth ap=0.1mm, and the amplitude A=25μm.

Embodiment 3: Drilling of cylindrical workpiece

The preparation of cutting tool and coolant is the same as that of Embodiment 1. This piece is to be drilled on one side of the cylinder, then it is necessary to process a semicircular auxiliary fitting 4 of metal material that matches the cylindrical workpiece 3 shown in Figure 2 at first, and then process the auxiliary fitting 4 A circular hole of a given size, this circular hole is equal to or slightly larger than the hole to be drilled on the workpiece 3 and gets final product so that the cutting tool can be stretched into. Note: Special tools are not required for metal fittings and drilling. Then, the semicircular auxiliary fitting 4 made of metal is fixed on the cylinder with a clamp and bonded, so that the drilling position on the auxiliary fitting 4 coincides with the drilling position on the workpiece 3 . Finally, the electroplated diamond drill bit is used for drilling, and the special cooling liquid of the present invention is poured into the drilling hole, and the specific processing parameters are set as feed rate f=0.01mm/r, cutting depth ap=0.2mm, and amplitude A=20μm.

As shown in Fig. 3, the holes are only processed on one side of the pre-drilled cylinder, so only semicircular auxiliary fittings 4 are required. Of course, it is also possible to process full-circle auxiliary accessories, but this will increase the consumables, and because it needs to fit very well, the full-circle hoop may not be easy to put on from one end, and it is not easy to remove, and the friction is strong. One side of the semicircle fits together, and the other side adopts a hoop-type tightening method, which is more convenient for installation and removal.

If you want to process drilling holes (such as radial through holes) on both sides of the cylinder, you can use two semicircular auxiliary fittings 4, and then fasten the two semicircular fittings to the workpiece, and then Holes on both sides are machined.

The present invention only provides a processing method for fiber-reinforced high-temperature composite materials from specific aspects. There is a large gap between the performance of the fiber and the matrix, and there is a lot of processing dust. Therefore, the use of this coolant will not only have good lubricity, but also can effectively absorb the dust generated during processing, and it is also environmentally friendly. The second is to independently design and manufacture the tool. Compared with ordinary tools, the handle of the tool is thicker, which can improve the vibration resistance of the tool. Other dimensions are designed according to the shape and size of the sample to improve the processing accuracy. In the material selection of the knife body, we choose two materials, one is cemented carbide, which is mainly used for rough machining, and the other is artificial diamond polycrystalline turning tool, which is mainly used for finishing the sample and reducing the surface roughness. The third is that the present invention targets the fiber-reinforced composite material woven with a three-dimensional structure, and processes the surface at an angle of 45° to the fiber direction, so that the best processing effect can be obtained. Fourth, the present invention has formulated special auxiliary accessories for the drilling of cylindrical workpieces, which can ensure that the position of the processing object is stable during the drilling process, thereby ensuring accurate aperture size.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of changes or modifications within the technical scope disclosed in the present invention. Replacement should be covered within the protection scope of the present invention.

Claims (10)

1. an aero-engine processing method for fiber reinforcement type high-temperature composite material, is characterized in that, work in-process uses a kind of cooling fluid, and described cooling fluid is the mixed liquor of water, glycerine, animal oil, and volume ratio is 8-10:4-5:4-5.

2. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 1, is characterized in that, described animal oil is lard.

3. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 1, is characterized in that, the volume ratio of described water, glycerine, animal oil is 2:1:1.

4. the aero-engine processing method of fiber reinforcement type high-temperature composite material according to claim 1 or 2 or 3, it is characterized in that, the compound method of described cooling fluid is:

First be at room temperature water and the glycerine mixing of 3.2-5:1 by volume ratio, become mixed liquor one, and be glycerine and the animal oil mixing of 0.8-1.25:2 by volume ratio, become mixed liquor two;

Then with the glycerine of same volume for benchmark, described mixed liquor one and mixed liquor two are mixed and namely obtain described cooling fluid.

5. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 1, it is characterized in that, also comprise and use a kind of cutter, described cutter comprises handle of a knife and blade, described handle of a knife adopts hard alloy steel, and described shank diameter is 1.5-5 times of regular knife shank diameter; Described blade adopts the mode of melting handle of a knife to submerge described handle of a knife, and the submerge shape of shank portion of described blade is inverted trapezoidal.

6. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 5, it is characterized in that, described cutter, when cutting, carries out machining along the plane at 45 ° with the machine direction of described fiber reinforcement type high-temperature composite material.

7. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 5, is characterized in that, the machined parameters of described cutter is: amount of feeding f=(0.01-0.04) mm/r; Cutting depth ap=(0.05-0.2) mm; Amplitude A=15-30 μm.

8. the processing method of aero-engine fiber reinforcement type high-temperature composite material according to claim 7, is characterized in that, the machined parameters of described cutter is: amount of feeding f=0.02mm/r; Cutting depth ap=0.1mm; Amplitude A=25 μm.

9. want the processing method of the aero-engine fiber reinforcement type high-temperature composite material described in 1 or 5 according to right, it is characterized in that, also comprise the method holed in the curvature surface of the workpiece of described fiber reinforcement type high-temperature composite material:

First make the auxiliary accessories of fitting completely with the curvature surface of workpiece, and described auxiliary accessories is holed in advance, as cutter access aperture;

Then described auxiliary accessories and described workpiece are fitted fixing, and by corresponding with the bore position on described workpiece for the position that described auxiliary accessories is holed;

Finally put in cutter from the drill hole of described auxiliary accessories to hole at workpiece.

10. want the processing method of the aero-engine fiber reinforcement type high-temperature composite material described in 9 according to right, it is characterized in that, the bore dia on described auxiliary accessories is equal to or slightly greater than the hole that described workpiece will bore.